ALBUQUERQUE, N.M., Aug. 23 -- The US Department of Energy's Sandia Laboratories are developing a tiny remote sensor that relies on optics and microelectromechanical systems (MEMS) to detect dangerous gases from up to two miles away. Called the Polychromator, the device is a joint effort of Sandia Labs, the Massachusetts Institute of Technology -- which is designing the MEMS structures -- and Honeywell, which is performing the fabrication.The Polychromator uses a variation on a conventional gas analysis technique known as correlation spectroscopy. The device passes IR radiation through a sample gas that imparts a spectral pattern to the radiation. This pattern is then compared with known spectra of reference gases; as each gas has a distinct spectral pattern, this correlation allows the sample gas to be identified quickly. In touting the benefits to the Polychromator's user, Sandia researcher Mike Butler, one of the device's inventors, said, There's no need to obtain a sample of the gas or even get close to it. Instead, the detection is made from a safe one or two miles away.